1. Field of the Invention
The present invention relates to end closures for containers having a push open lid to provide access to the material within the container. More particularly, the present invention relates to an end closure having a push open lid portion which includes a member which cooperates with the lid portion to hold it in an open position.
2. Description of the Related Art
Granular products such as garden chemicals, grated cheese, coffee creamer, sugar and seasonings are typically packaged in containers with plastic closures having rotatable portion with one or more permanent openings therethrough which selectively provides access to an opening through a lower portion of the container. The opening through the lower portion is conventionally defined by an openable lid portion which is pushed toward the interior of the container thus breaking a seal between the openable lid portion and the remainder of the container closure. Once is the seal is broken, the openable lid portion bends about a living hinge permanently affixing the openable lid portion with the remainder of the container closure.
In these containers, the end closure initially seals the container prior to use, and when it is desired to open the container to access its contents, the rotatable portion of the lid can be rotated to align its largest opening with the openable lid portion. The openable lid portion is forced open by applying pressure thereto rupturing a frangible seal and causing the openable lid portion to bend about the hinge portion. The rotatable lid portion can again be rotated when it is desired to close the open lid so that the non-perforated portion of the rotatable lid portion covers the opening defined by the openable lid portion.
These containers provide the advantage of selectively accessing the contents thereof, while providing a means to close the same between uses. However, a disadvantage with such end closures is that the lid portion which was pushed down to access the material in the container tends to flex toward its initially closed position, due to the resilience of the hinge portion. This causes the pour opening to be restricted in size, particularly when the container is inverted to pour powdered substances therefrom. There are times when the lid portion can completely block the opening. Therefore, it would be desireable to provide a structure which retains the openable lid portion in an open position so as to not interfere with accessing the container contents.
FIGS. 1-7 show various prior attempts to develop end closures that exhibit a type of flat rotor that was rotatably retained on a base without use of a rivet type connector or a mechanism to hold a press-open lid in an open position.
FIGS. 1 and 2 correspond to a type of end closure suitable for placement at the end of a container to close the interior. The end closure is comprised of a base and a rotor retained on the base and in a central portion of the base which extends radially outwardly from the rotor. The periphery of the rotor is provided with a raised or upwardly extending edge that includes a substantially C-shaped cross-section annular ring that corresponds to a reverse C-shaped cross-sectional retaining groove formed within the base. The bottom surface of the rotor was essentially a flat planar surface and included a cut-out opening and shaker openings. The base included a smile-shaped knockout panel which would be opened by removing the entire piece of plastic. The base was also characterized by two levels, one corresponding to the surface that extended radially outwardly from the rotor, the other located beneath the rotor.
The end closure shown in FIGS. 3-5 is another version where the rotor, so marked, also had a flat planar bottom surface. The rotor was held in the base, as marked, by means of an annular extension projecting slightly beyond the peripheral edge of the rotor and a mating groove formed in the base. Both the annular extension and groove were radiused. The bottom surface of the rotor was spaced above the upper surface of the base against which it was positioned forming an open space therebetween in which debris or material from the container could collect. Also, the radiused extension/groove approach for retaining the rotor on the base was not sufficiently positive to hold the rotor in place and provide a suitable seal for the contents inside the container.
The end closure shown in FIGS. 6-7 is a closure that holds the openable lid open. The bottom plan view of the base in FIG. 6 and the cross-sectional view in FIG. 7 show the use of two tapered conical projections that extended downwardly from the bottom surface of the base toward the interior of the container on which the end closure would be used. The push open lid or flap is characterized by a straight hinge along its rear edge. Two straight sides diverge at oblique angles away from opposing ends of the hinge toward the front of the lid terminating at an arched front edge which joints the outer ends of those straight sides. The straight sides provide a special shape that will pass beyond the tapered projections to the position shown in FIG. 7 with minimum interference yet provide sufficient contact so that the projections hold the flap open. Depending upon the stiffness of the plastic of the hinge and the lid, the lid would need to be bent beyond 90.degree. to move the lid beyond the projections in order to arrive at the position shown for the flap in FIG. 7. FIGS. 6a and 6b show top and bottom plan views of the rotor used for this end closure. The rotor was characterized by planar top and bottom surfaces, by a square cornered peripheral edge that mated with a radiused groove, as shown in FIG. 7, which was similar to the groove shown in FIG. 5 for retaining the rotor.
U.S. Pat. No. 4,969,572 discloses an end closure having a push open lid portion, wherein the underside of the openable lid portion includes members which cooperate with elements disposed on the underside of the end closure, for retaining the lid in an open disposition. A disadvantage of this closure is that the lid must be bent 90 degrees for it the lid member to engage the retaining elements. Also, this closure requires that the retaining elements and lid members be molded on the underside of the end closure and lid respectively, which increases the cost of the end closure.